Comment 1 for bug 481714

Castalia, if I remember correctly, the system-beeps were muted in Karmic to deal with the reactivation of some feature in the latest kernel. For whatever reason, I can not remember, but that kernel code caused the system to beep quite a bit and so it was muted to save people's sanity.

If you check your amixer settings, you should be able to unmute it to see if the beeping issue occurs for you.